Regenerative railway braking system

1. A mechanical regenerative braking system for installation on a bogie of a non-powered railway vehicle, the regenerative system including:

an energy storage system for storing energy in mechanical or kinetic form; wherein the energy storage system includes a flywheel mounted on an axle of the bogie by means of a bearing assembly that allows the flywheel to rotate independently from the axle of the bogie; wherein

size of flywheel and angular velocity determine how much energy can be stored in the flywheel for later use;

a transmission system which is selectively operable between different modes including:

i) a braking mode in which it transmits mechanical or kinetic energy from the axle of the bogie to the energy storage system;

ii) a drive mode in which it transmits mechanical or kinetic energy from the energy storage system to the axle of the bogie; wherein

in the drive mode speed of the flywheel will reduce until it reaches the speed at which the system is fully discharged; wherein

once a signal from the flywheel speed sensor indicates that the flywheel has reached the speed at which the system is fully discharged, the drive mode will be deactivated; and

iii) an idle mode in which the energy storage system contains stored energy but is neither actively being further charged nor is applying a tractive effort to the axle of the bogie; and

a control unit which is, in use, in communication with a prime mover and the transmission system so as to receive control signals from the prime mover and automatically operate the mode of the transmission system in response to the control signals.

2. The mechanical regenerative braking system according to claim 1 , wherein the modes of the transmission system include:

i) an isolation mode in which the transmission system is disengaged from the axle of the bogie and the energy storage system; and

ii) a self-discharge mode in which the energy storage system is disengaged from the transmission system and energy, is dissipated from the energy storage system.

3. The mechanical regenerative braking system according to claim 1 , wherein the non-powered vehicle is a railway wagon.

4. The mechanical regenerative braking system according to claim 1 , wherein the transmission system is in the form of a continuously variable transmission (CVT).

5. The mechanical regenerative braking system according to 1 , including a transmission-to-axle link for transmitting mechanical or kinetic energy between the axle of the bogie and the transmission system.

6. The mechanical regenerative braking system according to claim 1 , wherein the energy storage system includes a flywheel.

7. The mechanical regenerative braking system according to claim 1 , wherein the regenerative braking system includes a transmission-to-energy storage system link.

8. The mechanical regenerative braking system according to claim 1 , wherein each axle of railway bogie includes the regenerative braking system installed on each axle of bogie, wherein the braking systems are operable independently from one another having its own braking system, transmission system and energy converters.

9. A regenerative energy management system for a train having a prime mover and a number of railway wagons, the energy management system including a number of regenerative braking systems according to claim 1 installed on each of the railway wagons, wherein control units of the regenerative braking systems are independently in communication with the prime mover.

10. A method of operating a regenerative braking system of a bogie of a non-powered railway vehicle, the system including an, energy, storage system for storing energy in mechanical or kinetic form; wherein the energy storage system includes a flywheel mounted on an axle of the bogie by means of a bearing assembly that allows the flywheel to rotate independently from the axle of the bogie; wherein size of flywheel and angular velocity determine how much energy can be stored in the flywheel for later use; a transmission system and a control unit for controlling a transmission system, the method including:

receiving a control signal;

switching between different modes of operation in response to the control signal, wherein different modes include the following:

i) a braking mode in which the energy storage system is engaged with the transmission system in such a manner that a force is applied to wheels of the bogie acting in a direction braking the bogie wheels, thereby charging the energy storage system; wherein if axle speed velocity is larger than vehicle translational velocity, a torque applied by the braking system will be reduced or the system will disengage;

ii) an idle mode in which the energy storage system contains stored energy but is neither actively being further charged nor is applying a tractive effort to the axle of the bogie; and

iii) a drive mode in which the energy storage system is engaged with the transmission system in such a manner that a force is applied to the wheels of the bogie acting in a direction driving the bogie wheels; wherein a torque applied by the regenerative braking system is reduced during the drive mode if axle speed velocity is larger than the vehicle translational velocity; wherein in the drive mode speed of a flywheel will reduce until it reaches the speed at which the system is fully discharged; wherein once a signal from a flywheel speed sensor indicates that the flywheel has reached the speed at which the system is fully discharged, the drive mode will be deactivated, and wherein the driving mode may be deactivated by a speed sensor signal, measuring speed of a vehicle, indicating that the energy storage system is fully discharged.

11. A method according to claim 10 , wherein the different modes further include:

iv) an isolation mode in which the transmission system is disengaged from the axle of the bogie and the energy storage system; and

v) a self-discharge mode in which the energy storage system is disengaged from the transmission system and energy is dissipated from the energy storage system.

12. A method according to claim 11 , wherein the isolation mode is activated by a signal that detects failure or defects in any system component.

13. The method according to claim 11 , wherein the self-discharge mode is activated by a signal that detects a system component failure or by a signal that system components need to be shut down at the end of a journey.

14. The method according to claim 11 , wherein the self-discharge mode is deactivated by a speed sensor signal indicating that the energy storage system has discharged.

15. The method according to claim 10 , wherein the braking mode is activated by a signal from a lead locomotive during braking.

16. The method according to claim 10 , including maintaining the torque that is applied to the axle of the bogie during the braking mode and/or driving mode by the regenerative braking system within a range ensuring that there is no slippage between the wheels of the bogie and rail.

17. The method according to claim 16 , including monitoring the slippage by comparing vehicle translational velocity with velocity determined from wheel or axle speed of the bogie.

18. The method according to claim 17 , including reducing the torque being applied by the regenerative braking system during the braking mode or driving mode if the axle speed velocity is larger than the vehicle translational velocity.

19. The method according to claim 10 , wherein the braking mode is deactivated by a speed sensor signal, indicating that the energy storage system is fully charged.

20. The method according to claim 10 , including measuring the coupler forces of the non-powered railway vehicle and deactivating the braking mode or driving mode when the coupler force signal is within a predetermined range.

21. The method according to claim 10 , wherein the idle mode is activated by a signal that a train is coasting.

22. The method according to claim 10 , including measuring the coupler forces, wherein the idle mode is activated when by a signal that the coupler forces are within a predetermined range.

23. The method according to claim 10 , wherein the drive mode is activated by a signal that power is required.

24. The method according to claim 23 , wherein the signal indicating that power is required is received from a lead locomotive.